1. Field of the Invention
The present invention relates to a method and a plant for supervising and controlling field lighting at an airport, and which optionally include presence detectors.
2. Description of the Related Art
The traditional implementation of a system for field lights is as follows.
High-intensive and low-intensive lightings along approach paths, runways and taxiways are supplied from one or more supply points, so-called cabinets or stations situated in the airport field, usually two for a field with one runway. These supply points are fed with high voltage unregulated electricity which is transformed down to 380/320 V and the supply points contain regulator equipment, thyristor or transducer regulators or regulating transformers for converting the unregulated electricity into controlled, regulated electric power for supplying the light units, which takes place via several power supply loops. Supply takes place in two principally different ways, i.e. by series of parallel feed to the lightings. Each lighting is provided with a transformer for retransformatting the electricity to a suitable low voltage for supplying the lighting with power, in addition, the supply points also contain a supervisory system which monitors the status of the field lighting plant, e.g. such as to ensure that a sufficiently large number of light units function, that the intensity of the light units is correct etc. The supply points, i.e. the cabinets, communicate via a communication link, inter alia with the traffic control tower supervising and operating panel, from which the regulating and supervisory systems are controlled, and at which information from the systems is received. This communication takes place via separate wire pairs for each function, or with time multiplex transmission on wires or optical fibers.